The fare you actually pay is determined also by your return date - and the flight time you choose on the days of travel. If I return as planned on February 24, the return fare will be £123. If I wait until the next day, it will be £98. Travelling out on February 22, of the eight flights available, I could travel on five of them at the £98 return fare but, coming back, just one is available at £98 - using any of the others increases the fare to £113 or £128.